Pipe clamps are used on pipes of different diameters. It is known to use pipe clamps to connect flanged pipes as an alternative to a bolted flange connection. It is also known to use pipe clamps to connect a flanged pipe to a sealing end cap. Pipe clamps that are to connect relatively large pipes, and in particular submerged pipes, must enable closing with great force. Patent document WO 2005/116505 discloses an example of a two-part pipe clamp for use in underwater operations. It is known within the art that such a pipe clamp may have three parts.
Pipe clamps connecting submerged pipes may be provided with a screw mechanism on one side of the pipe, and the screw may be oriented perpendicularly to the longitudinal axis of the pipe, A threaded bolt is tightened or loosened by means of a so-called ROV (Remote-Operated Vehicle) which is provided with a rotary tool with a gear transmission to apply a sufficient torque to the bolt. It is essential that the pipe clamp is tensioned with the correct torque around the pipe. If torque is too small, the connection is not reliable, and if the torque is too great, the connection may be damaged. When a new pipe damp is fitted, the tightening torque of the bolt is measured by means of the rotary tool, The rotary tool is calibrated on the surface before the ROV submerges. The ROV tightens the bolt until the desired torque is read on the rotary tool.
Pipe damps holding together submerged pipes that are used in the recovery of petroleum, for example, are dimensioned for a lifetime of at least 20 years. During the lifetime of the pipe clamp it may be necessary to perform maintenance work on the pipeline so that the pipe clamp must be opened to give access to the inside of the pipeline. After maintenance work has been performed, the pipe clamp is to be tensioned again to the desired torque. In the course of the time during which the pipe clamp has been submerged, sediment has covered portions of the surfaces and parts of the pipe clamp. Corrosion may have arisen in the joints and threads of the pipe clamp. This results in there being no guarantee, even if the measured torque of the rotary tool corresponds to the measured torque when the bolt was tightened as the pipe clamp was being fitted the first time, that the pipe clamp has been tensioned to the same torque around the pipe.